Ohm intelligent car battery refuses to die

It's a terrible feeling. You're already late for wherever you're going, so you rush into the car and slam the door shut. You put the key in, give it the usual twist and ... nothing, not a peep. Dead battery. Many a driver has experienced this issue at one point or another, and most would prefer not to repeat it. The Ohm smart battery was designed to help make sure you never do.

The car battery is one of those items that most people really don't want to think too much about. They want to replace it as infrequently as possible and then have it just work, every time, without fuss.

It's no surprise, therefore, that the car battery is largely the big, heavy, electrochemical block that it was generations ago. It does its job pretty well, and you don't really have to think about it much.

Silicon Valley startup Ohm Laboratories believes there's some room for improvement and new thinking, though. More than just a battery, its Ohm battery is an energy storage and management system in a battery-sized case. Its integrated processor monitors power level and automatically cuts power when the battery drops to a critical level. So if you accidentally leave your lights on, Ohm will shut itself down before going dead and then turn itself back on within about 30 seconds when you start up the car.

The self shut-off system is a handy feature to have during the battery's effective life, but there's one dead battery issue it can't help with: end of life. That's why the battery also has a replacement warning system. The system beeps to let you know it's time for replacement, and Ohm says it works more quickly and accurately than the battery warning light on the dashboard.

Unlike the lead acid construction of typical car batteries, Ohm uses a combination of lithium iron phosphate batteries and supercapacitors. It's the supercapacitors that deliver the quick burst of electricity for starting. The LiFePO4 batteries, in turn, keep the supercapacitors charged when the engine is off, so they're ready to go when you twist the key or punch the ignition button.

Ohm says that the LiFePO4/supercapacitor configuration gives the battery a seven-year lifespan, which is around double that of the average lead acid battery. It also makes claims of better performance in cold weather.

Assuming it doesn't gain any bulk before production, the Ohm is also a lot lighter than a lead acid battery. The estimated 6-lb (2.7-kg) weight looks light right off the bat, but when you compare it to the ~35 pounds (15.9 kg) a group size 35 lead acid battery weighs, it's downright feathery. That loss not only cuts down your vehicle's weight, it makes the Ohm easier to handle during replacement.

While lighter internally, the Ohm's body is sized to slide into existing cars' battery wells and connect just like a lead acid car battery. The unit comes in two sizes – one designed to fit neatly in cars that accept group size 35 batteries and one designed for smaller battery wells. You can use the reference tool on Ohm's Indiegogo page to find out if the battery is a match for your car.

Ohm designers admit one downside to their design: a small 10 Ah reserve capacity. This could be a problem if you rely on the battery to run electrical equipment and accessories with the engine off, and Ohm suggests sticking with a standard lead acid battery if that's the case. Thanks to the Ohm's self shut-off, at least you won't risk running the battery dead.

The Ohm team says that it has tested its battery over thousands of miles but still has a lot of testing left to do on aspects like life cycle, temperature rating and battery management circuitry. Its numbers are not finalized, so the aforementioned seven-year lifespan, 10 Ah reserve capacity and 6-lb weight are still subject to change, as are the 500 peak cold cranking amps and -22 to 122° F (-30 to 50° C) operating range.

Ohm has worked with the seed funders at Y Combinator and has turned to Indiegogo to raise the additional funding it needs to complete testing, finalize the design, purchase tooling and get production started. It is closing in on its US$50,000 goal with 23 days left to go and the lowest early bird pledge levels have sold out, but the Ohm battery is still available at $199, a $20 discount off the estimated retail price. That price is probably a lot higher than you'd spend on a lead acid battery at the local auto parts store, but if the Ohm performs as promised, it may be worth it.